hard-hearted
stonyhearted
unfeeling
bowelless
callous
coldhearted
cruel
disagreeable
dog-eat-dog
fierce
flinty
hard
hard-boiled
hardhearted
harsh
heartless
ill
impiteous
inclement
inexorable
inhospitable
merciless
obdurate
pitiless
relentless
remorseless
ruthless
stony
unaffectionate
unamiable
unbenign
unbenignant
uncompassioned
uncordial
unemotional
unforgiving
ungenial
ungracious
unkind
unkindly
unloving
unmerciful
unpitiful
unpitying
unremorseful
unsympathetic
compassionate